Video projectors can be arranged in arrays of two or more projectors in order to project a tiled composite image in which each projector in the array projects a component image that forms a corresponding portion of the composite image. When projecting large images, video projector arrays can provide enhanced brightness and resolution of the composite image and can reduce the requisite distance between the projectors and the surface onto which the composite image is projected. When projecting a composite image via a projector array, it can be desirable to match or blend the adjacent edges of the component images in order to provide the appearance of a seamless composite image.
The component image produced by each projector in the projector array is formed as an array of pixels. The resolution of each image is affected by the pixel pitch (e.g., size or diameter) and the image size (e.g., the size of the pixel array that forms the image). The pixel pitch and image size help determine the pixel density (e.g., pixels per inch) of the image. For example, an image may have a pixel pitch of about 0.030 inch and may have an image size of 640×480, 800×600, or 1024×768 pixels. The pixel pitch and/or image size for a projector can, of course, vary.
In order to achieve the appearance of a single seamless composite image, it may be necessary to arrange or adjust the projectors in the array so as to eliminate gaps between the component images. It may also be necessary to align the projectors in the array such that the pixels that make up the periphery of the component images align correctly with the pixels of adjacent component images.
In the past, multiple-projector composite image projection systems have relied heavily on “in-situ” alignment procedures in which projectors are arranged in an array and subsequently adjusted to align the projectors relative to one another. In-situ alignment of projectors relative to one another can, however, produce cumulative errors that are increasingly and exponentially difficult to control as the size of the projector array increases. In-situ alignment of projectors can also result in downtime for the projector array when a projector is replaced, such as during repairs, and alignment of the replacement projector is required.